BeiDou-Based Passive Radar Signal-to-Noise Ratio Enhancement Method

As a special bi/multi-static radar system,passive radar has significant advantages such as low cost,anti-stealth and anti-jamming.Compared with conventional sources of opportunity,Bei Dou satellite has the characteristics of wide coverage,strong antiblocking ability,safety and reliability,etc.Therefore,the passive radar based on Bei Dou satellite transmitter provides a performance in the fields of wide-area continuous covert detection and ground imaging.However,the ground power density of Beidou satellite signals is lower than that of conventional radar signals.Therefore,how to enhance the signal-to-noise ratio of passive radar is one of the key issues for its practical application.Aiming at the problems of low signal-to-noise ratio of echo detection and large background noise of radar image,this thesis carried out relevant theoretical research and simulation verification work on the Bei Dou-based passive radar signal-to-noise ratio enhancement method.The main research contents are as follows:1.Based on the system parameters and signal characteristics of the Beidou satellite,a Bei Dou-based passive radar echo model was established,and the space-time variation characteristics of the distance migration and Doppler migration of the moving target echo were analyzed,which provides a theoretical basis for the subsequent research on passive radar signal-to-noise ratio enhancement methods.2.Aiming at the problem that the passive radar moving target echo detection signalto-noise ratio is too low,the influence of the echo signal-to-noise ratio on the detection performance of the Bei Dou-based passive radar is studied,and a signal-to-noise ratio enhancement method based on space-time integration is proposed.Through long-time integration and space integration of multi-satellite sources of opportunity,the signal-tonoise ratio of target echo detection is effectively enhanced,which provides a guarantee for high-reliability target detection.3.Aiming at the problem of low signal-to-noise ratio and blurred edges in passive radar images,the influence of receiver thermal noise on the image definition of Bei Doubased passive radar is studied,and a fast sharpening non Local mean signal-to-noise ratio enhancement method is proposed.Through non-local mean processing after edge sharpening and integral acceleration,the signal-to-noise ratio of passive radar images is effectively enhanced,which provides a guarantee for the high-quality application of radar imaging.In this thesis,the effectiveness of the above method is verified through theoretical analysis,simulation experiments and measured data tests,and the results show that the above method can achieve effective enhancement of the passive radar signal-to-noise ratio based on Bei Dou transmitter,so as to achieve effective target detection and imaging.